Tube expander

ABSTRACT

A tube expander comprising an elastomer bushing which expands outwardly when compressed between two bushings pulled together by a cable, which is pulled through a plurality of short lengths of tubing capable of folding against each other when the cable is slack, allows the tube expander to fit through manways and into corners of channel heads of heat exchangers to expand the tubes a predetermined distance from one end thereof.

United States Patent 1 91. 1111 3,831,413 Glatthorn Aug. 27, 1974 [54]TUBE EXPANDER 3,691,609 9/1972 lce, Jr. et al 29/252 Inventor: Raymond Ea m, FOREIGN PATENTS OR APPLICATIONS Petersburg, 1,199,258 6/1959 France29/505 [73] Assignee: Westinghouse Electric Corporation,

. Pittsburgh, Pa. Primary Examiner-Richard J. Herbst Nov. 1 Attorney,Agent, OI FirmF. Baehl', Jr.

[21] Appl. No.: 302,951 [57] ABSTRACT A tube expander comprising anelastomer bushing (g1. 725;},3925/(2); which expands outwardly whencompressed between [58] Fieid 62 370 two bushings pulled together by acable, which is pulled through a plurality of short lengths of tubing72/466 29/523 269/48'1 capable of folding against each other when thecable is [56] References Cited slack, allows the tube expander to fitthrough manways and into corners of channel heads of heat ex- UNITEDSTATES PATENTS changers to expand the tubes a predetermined disl,0l6,7702/1912 Persons tance from one end thereof, 2,507,979 5/1950 Kelar3,252,210 5/1966 Bowden 8 Claim, 3 Drawing Figures TUBE EXPANDERBACKGROUND OF THE INVENTION This invention relates to tube expanders andmore particularly to tube expanders which expand a tube a predetermineddistance behind the tube sheet. In heat exchangers, such as nuclearsteam generators in which the tubes are U-shaped, when a tube fails itis very difficult to remove the whole tube, however, it is desirable totake out a section of the tube for metallurgical examination. Beforeremoving the section of the tube it is desirable to expand the tubeadjacent one of the tube support sheets, to generally hold the tube inits normal position when one or both of the end portions are removed forinspection.

The expanding tool must be capable of being fed through a manway andaround a small radius so that it can fit in close quarters in thechannel head of the heat exchanger and must be able to be operable in aminimum amount of time when the heat exchanger is a nuclear steamgenerator as these vessels generally have a low level of radioactivity.

SUMMARY OF THE INVENTION Apparatus for expanding a tube a predeterminedlength from one end thereof when made in accordance with this invention,comprises a cable, a bushing attached to the cable, an elastomer tubularmember slidably disposed over the cable, and a device for drawing thecable through the tubular members, whereby the elastomer tubular memberis compressed and expands in a radially outward direction therebyexpanding a portion of the tube adjacent thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of thisinvention will'become more apparent from reading the following detaileddescription in connection with the accompanying drawings, in which;

FIG. 1 is a perspective view of a tube expander made in accordance withthis invention;

FIG. 2 is a partial perspective view showing how the tube expander foldsto fit into clamped quarters; and

FIG. 3 is a partial elevational view of heat exchanger having a tubeexpander disposed to expand a tube adjacent a tube support sheet.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingsin detail, FIG. 1 shows an apparatus 1 for expanding a tube apredetermined distance from one end thereof. The apparatus or tubeexpander 1 comprises a wire rope or cable 3, a first bushing 5 fastenedto one end of the cable 3 by soldering or other means, and an elastomertubular member 7 made of polyurethane or other resilient material,slidably disposed on the cable 3 adjacent the first bushing 5. A secondbushing 9 is slidably disposed on the cable 3 adjacent the elastomertubular member 7 and a plurality of tubular members or pipes 11 areslidably disposed on the cable 3.

The bushings 5 and 9 generally have two cylindrical surfaces, a shortportion 12 adjacent the elastomer tube member 7 which is slightly largerin diameterthan the elastomer tube member 7 and slightly smaller indiameter than the inside diameter of the tube to be expanded. Thus,preventing the elastomer from flowing into the clearance between thebushing and the tube to prevent damage to the elastomer as it iscompressed between the bushings.

The tube expander 1 also comprises means for drawing the cables 3through the tubular members 7 and 11. The means for drawing the cable 3through the tubular members comprises a base or bucking plate 13, a pairof hydraulic cylinders 15 fastened to the base plate 13, and a bridgeplate 17 also fastened to the hydraulic cylinders 15. The bridge plate17 has a semi-circular grooved cable support 19 cooperatively associatedtherewith.

The cable 3 loops over the cable support 19 andis tied to itself by acable clamp 21. The base plate 13 has a centrally disposed hole 23through which the cable is threaded.

A hydraulic pump 25 which may be hand operated, as shown, or motoroperated, supplies pressurized hydraulic fluid to the cylinders 15,which expand as pressurized fluid is supplied thereto, drawing the cable3 through the tubular members 7 and 11 and causing the bushings 5 and 9to axially compress the elastomer tube member 7 which expands radiallyoutwardly to expand the tube.

As shown in FIG. 2, the tubular members 7 and 11 and bushings 5 and 9fold with respect to each other when the hydraulic cylinders 15 are notextended allowing the apparatus to fit through a manway and into a tubeof heat exchanger even though there may be lim-' ited access to the tubeas it may be adjacent the wall of a spherical shaped channel head.

As shown in FIG. 3, the operation of the tube expander 1 is as follows;a predetermined number of tubular members 11 are threaded on the cable 3and the cable is threaded through the hole 23 in the base plate 13 andlooped over the cable support 19 and clamped to itself by the cableclamp 21 securing the end of the cable to the cable support. Sufficientslack is provided in the cable so that the tubular members and bushingscan fold with respect to each other as shown in FIG. 2. The number andlength of the tubular members is determined by the distance from the endof a tube 31 to a support sheet 35 or a distance from a tube sheet 33 toa support sheet 35, so as to position the elastomer bushing adjacent thelocation where the tube is to be expanded. The tube expander 1 is fedthrough a manway (not shown) and the end containing the elastomer member7 is fed in to the tube 31. When the base plate 13 abuts the tube sheet33 the hydraulic pump 25 is operated supplying pressurized fluid to thecylinders 15 causing the cylinders to expand moving the bridge plate 17away from the support plate 13 and drawing the cable 3 through thetubular members which result in the bushings 5 and 9 compressing theelastomer tubular member 7 in an axial direction, which causes theclastomer tubular member 7 to expand radially thereby contacting thetube 31 and expanding it radially outwardly into engagement with thetube support sheet 35, so that a portion of the tube 31 can be cut offand extracted for metallurgical tests and the portion of the tuberemaining in the heat exchanger will be securely fastened in its normalposition. Thus, preventingthe cut off tube from contacting adjacenttubes and damaging them, as the cut off tube vibrates as a result offluid flow or vibrations induced by associated equipment.

Since the tubular members can fold, the tube expander is operable incramped quarters and no time is required for assembly in place, the tubeexpander can be assembled in the shop to expand a tube a predetermineddistance from the end thereof and a minimum amount of time is requiredin utilizing the tube expander 1. This is extremely important when theheat exchanger is radioactive and the time an operator can spend thereinis limited.

What is claimed is:

1. Apparatus for expanding a heat exchanger tube a greater distance fromone end thereof than the clearance between the one end of the tube andan adjacent wall of the heat exchanger, said apparatus comprising acable, a tubular bushing member attached to the cable, an elastomertubular member slidably disposed over said cable, a plurality of rigidsegmented tubular members slidably disposed over said cable, all of saidtubular members being cooperatively associated with the cable to alloweach tubular member to fold with respect to the adjacent tubular member,and means for drawing the cable through said tubular members, saidelastomer tubular member being so disposed with respect to the othertubular members that when the cable is drawn through the tubular memberssaid elastomer tubular member is compressed in an axial directioncausing it to expand in a radially outward direction, thereby expandinga portion of said tube adjacent thereto.

2. Apparatus as set forth in claim 1 and further comprising a secondtubular bushing member slidably disposed over the cable, each bushinghaving a cylindrical surface slightly smaller in diameter than the tubeand slightly larger in diameter than the elastomer tubular member.

3. An apparatus as set forth in claim 2, wherein the cylindrical surfaceon the first mentioned bushing is adjacent the elastomer tubular memberand the cylindrical surface on the second mentioned bushing is alsoadjacent the elastomer tubular member.

4. An apparatus as set forth in claim 2, wherein the bushing has anadditional cylindrical surface smaller in diameter than said firstmentioned cylindrical surface.

5. Apparatus as set forth in claim 2, wherein cylindrical surface of thebushing is slightly larger in diameter than the elastomer tubularmember.

6. Apparatus as set forth in claim 1, wherein the means for drawing saidcable through said tubular members comprises at least one hydrauliccylinder disposed to draw said cables through said tubular members assaid hydraulic cylinder is expanded.

7. Apparatus as set forth in claim 1, wherein the means for drawing saidcable through said tubular members comprises a pair of hydrauliccylinders cooperatively associated to draw said cable through thetubular members as said cylinders are extended.

8. Apparatus as set forth in claim 1, wherein the elastomer tubularmember is made of polyurethane.

1. Apparatus for expanding a heat exchanger tube a greater distance fromone end thereof than the clearance between the one eNd of the tube andan adjacent wall of the heat exchanger, said apparatus comprising acable, a tubular bushing member attached to the cable, an elastomertubular member slidably disposed over said cable, a plurality of rigidsegmented tubular members slidably disposed over said cable, all of saidtubular members being cooperatively associated with the cable to alloweach tubular member to fold with respect to the adjacent tubular member,and means for drawing the cable through said tubular members, saidelastomer tubular member being so disposed with respect to the othertubular members that when the cable is drawn through the tubular memberssaid elastomer tubular member is compressed in an axial directioncausing it to expand in a radially outward direction, thereby expandinga portion of said tube adjacent thereto.
 2. Apparatus as set forth inclaim 1 and further comprising a second tubular bushing member slidablydisposed over the cable, each bushing having a cylindrical surfaceslightly smaller in diameter than the tube and slightly larger indiameter than the elastomer tubular member.
 3. An apparatus as set forthin claim 2, wherein the cylindrical surface on the first mentionedbushing is adjacent the elastomer tubular member and the cylindricalsurface on the second mentioned bushing is also adjacent the elastomertubular member.
 4. An apparatus as set forth in claim 2, wherein thebushing has an additional cylindrical surface smaller in diameter thansaid first mentioned cylindrical surface.
 5. Apparatus as set forth inclaim 2, wherein cylindrical surface of the bushing is slightly largerin diameter than the elastomer tubular member.
 6. Apparatus as set forthin claim 1, wherein the means for drawing said cable through saidtubular members comprises at least one hydraulic cylinder disposed todraw said cables through said tubular members as said hydraulic cylinderis expanded.
 7. Apparatus as set forth in claim 1, wherein the means fordrawing said cable through said tubular members comprises a pair ofhydraulic cylinders cooperatively associated to draw said cable throughthe tubular members as said cylinders are extended.
 8. Apparatus as setforth in claim 1, wherein the elastomer tubular member is made ofpolyurethane.